If we swap its arguments, SkTaskGroup::batch() _is_ sk_parallel_for.

tests/OnceTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOnce.h"
 #include "SkRunnable.h"
 #include "SkTaskGroup.h"
@@ skipping 14 matching lines @@
     SkOnce(&st_once, add_five, &x);
     SkOnce(&st_once, add_five, &x);
 
     REPORTER_ASSERT(r, 5 == x);
 }
 
 SK_DECLARE_STATIC_ONCE(mt_once);
 DEF_TEST(SkOnce_Multithreaded, r) {
     int x = 0;
     // Run a bunch of tasks to be the first to add six to x.
-    sk_parallel_for(1021, [&](int) {
+    SkTaskGroup().batch(1021, [&](int) {
         void(*add_six)(int*) = [](int* p) { *p += 6; };
         SkOnce(&mt_once, add_six, &x);
     });
 
     // Only one should have done the +=.
     REPORTER_ASSERT(r, 6 == x);
 }
 
 static int gX = 0;
 static void inc_gX() { gX++; }
 
 SK_DECLARE_STATIC_ONCE(noarg_once);
 DEF_TEST(SkOnce_NoArg, r) {
     SkOnce(&noarg_once, inc_gX);
     SkOnce(&noarg_once, inc_gX);
     SkOnce(&noarg_once, inc_gX);
     REPORTER_ASSERT(r, 1 == gX);
 }